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P. Manikandan ¹, K. Manjula Rani ¹, S. V. Priya ¹, V. N. Kowshalya ¹

Affiliations
1 Department of Chemistry, Kongu Engineering College, Perundurai, Erode-638 052, T. N., IN

Abstract

The adsorption of hexavalent chromium, present in effluents of various industries such as electroplating, tannery, etc., on Coal Fly Ash (CFA) has been investigated in the present study. Parameters like contact time, adsorbent dose, pH and initial chromium ion concentration were studied in kinetic batch experiments at 25°C. Among all the parameters, pH of the solution was most effective for chromium removal. The adsorption of hexavalent chromium on CFA was found to be maximum at low pH. The adsorption data fit well with Langmuir and Freundlich isotherm models. The Langmuir adsorption isotherm to the systems yielded maximum adsorption capacity of 19.77 mg/g at the solution pH of 2. Results showed that the pseudo second order kinetic model best correlate with the experimental data.

Keywords

Hexavalent Chromium, Adsorption Kinetics, Langmuir Isotherm, Freundlich Isotherm, Acid Activated Coal Fly Ash.

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S. V. Priya ¹, R. Saratha ²

Affiliations
1 Dept. of Chemistry, Kongu Engineering College, Perundurai-638052, Erode, Tamilnadu, IN
2 Dept. of Chemistry, Avinashilingam University for Women, Coimbatore-641043, Tamilnadu, IN

Abstract

Corrosion inhibition of mild steel in 1 M HCl was investigated in the absence and presence of different concentrations of extract of Crossandra infundibuliformis leaves. Weight loss measurements and electrochemical studies were employed. The corrosion rate of mild steel and the inhibition efficiencies of the extract were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of mild steel in HCl media. Inhibition was found to increase with increasing concentration of the plant extract. The inhibitive actions of plant extract are discussed on the basis of adsorption of stable complex at the mild steel surface. Theoretical fitting of different isotherms, Langmuir, Temkin, Freundlich, Frumkin, Flory-Huggins and the kinetic thermodynamic model were tested to clarify the nature of adsorption. Polarisation curves revealed that this inhibitor act as a mixed type inhibitor and the inhibition efficiency up to 97.41% can be obtained. The surface analysis study confirms the corrosion of mild steel and its inhibition by the inhibitor.

Keywords

Mild Steel, Corrosion Inhibitors, Adsorption Isotherms, Inhibition Efficiency.

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